The present invention relates to a fungicidal composition comprising synergistically effective amounts of
(a) at least one acrylic acid morpholide of formula I ##STR3## in which R.sup.1 and R.sup.2 each independently represent hydrogen or halogen atom or an optionally substituted alkyl, alkoxy, alkenyl, alkynyl, alkadienyl, aryl, aryloxy, heteroaryl, cycloalkyl, cycloalkenyl, bicycloalkyl or heterocyclyl group, PA1 (b) and at least one fungicidal oxazolidinone of formula II ##STR4## in which R.sup.3 and R.sup.4 each independently represent hydrogen or an optionally substituted alkyl, alkenyl, alkynyl, alkadienyl, aryl, aryloxy, cycloalkyl, or cycloalkenyl group; and PA1 x is the efficacy in % compared with an untreated control upon treatment with a fungicidal active ingredient A at a dose rate a; PA1 y is the efficacy in % compared with an untreated control upon treatment with a fungicidal active ingredient B at a dose rate b; PA1 EE is the expected efficacy with a combination of fungicidal active ingredients A and B at a dose of a+b, respectively. PA1 R.sup.3 represents a hydrogen atom or a C.sub.1-4 alkyl group, in particular a methyl group, PA1 R.sup.4 represents a hydrogen atom, and PA1 Ar represents a phenyl group, optionally or substituted in the 4-position by a halogen atom or an alkyl, alkoxy, alkenyloxy, phenyl or phenoxy group. PA1 an acrylic acid morpholide of formula I, in particular, dimethomorph; PA1 at least one oxazolidone of formula II; in particular, famoxadone, PA1 a surface active agent; PA1 optionally a foam breaking agent, in particular, a mixture of perfluoroalkyphosphonic acids and/or perfluoroalkylphosphinic acids, in particular Defoamer.RTM. SF or Fluowett.RTM. PL, which are commercially available from Clariant GmbH (former Hoechst AG), Germany. PA1 (i) a container which comprises at least one fungicide of formula I, in particular dimethomorph, conventional adjuvants and carriers; PA1 (ii) a container which comprises at least one compound of formula II, in particular famoxadone, conventional adjuvants and carriers.
Ar represents an optionally substituted phenyl group; together with a fungicidally acceptable carrier and/or surface active agent.
The fungicidal compounds of formula I useful in the present invention are known from European Patent No. 0 120 321. U.S. Pat. No. 5,262,414 discloses mixtures of these compounds with contact fungicides. EP 0 393 911 discloses the method of using oxazolidinones of formula II as fungicides, and indicates that they can be mixed with other fungicides, vacterisides, acaricides, etc., including 4-[3-(4-chlorophenyl)-3-(3,4-dimethoxyphenyl)-1-oxo-2-propenyl]morpholine, a compound of formula I. However, there is no suggestion that the compounds of formula I with oxazolidinones of formula II, when admixed in a tank mix or when co-formulated, would exhibit synergistic effects. Moreover, there is no suggestion that a composition comprising a synergistic mixture of these compounds can be advantageously be used for controlling plant diseases caused by ascomycetes, basidiomycetes, deuteromycetes and oomycetes, e.g. Uncinula necator and Phytophthora infestans.
A mixture of fungicides shows synergistic effect if the fungicidal activity of the mixture is larger than the sum of activities of the separately applied compounds. The expected fungicidal activity for a given mixture of two fungicides can be calculated as follows (See Colby, S. R., "Calculating synergistic and antagonistic response of herbicide combinations", Weeds 15, pp 20-22 (1967): EQU EE=x+y-x.multidot.y/100
wherein
If the actual efficacy (E) exceeds the expected (calculated) one (EE), the mixture displays a synergistic effect.